1. The Field of the Invention
The present invention is in the field of wax-based compositions and dental treatment devices and other articles made from such compositions.
2. The Relevant Technology
Dental treatment trays and strips are commonly used to deliver bleaching compositions and medicaments to a user's teeth. “Trays” are pre-shaped barriers designed to fit over some or all of a user's teeth and can be customized or non-customized. Trays can be pre-loaded with an oral treatment composition or filled with a treatment composition by the user at the time of use. “Strips” are generally non-customized sheet-like barriers that include a treatment composition on one side or embedded within the barrier layer and which can be placed over and folded around a user's teeth in a tray-like configuration.
One type of customized dental tray is made by thermoforming a sheet of moisture-resistant thermoplastic polymer material, such as ethylene vinyl acetate copolymer (EVA), over a stone model of a user's teeth and then trimming the intermediate molded form to yield the desired tray-like shape. A blockout material can be applied to the stone model to form reservoirs in the customized tray, which can accommodate placement of additional treatment composition next to a person's tooth surfaces. Reservoirs can provide additional comfort by reducing orthodontic forces, particular with more rigid trays. Drawbacks of customized trays formed in this manner include the time and cost of forming an impression of a person's teeth, typically at a dentist office, using the impression to form the stone model, thermoforming the sheet, and trimming the molded form to yield the customized tray. The main benefit is that such trays typically provide the best fit, comfort and effectiveness in delivering a medicament to a user's teeth as compared to oral strips and other types of dental trays.
Another type of customized tray is made using a person's own teeth as the template (e.g., so called “boil-and-bite” trays). In a typical customization process a non-customized tray blank made from a thermally softenable polymer material is initially heated (e.g., in hot water or microwave oven) to temporarily soften the polymer tray material. The softened tray is then placed over the user's teeth and custom-formed to the user's teeth using forces applied by one or more of biting, suctioning, or externally applied pressure using fingers. When the customized tray has cooled sufficiently to retain its form, it can be removed from the user's mouth and is then ready for use. A drawback of self-customized trays is that they can be bulky and uncomfortable, particularly when in the form of sports mouth guard, which typically have a wall thickness of at least 3 mm and usually more. And while there have been patents directed to thin-walled, self-customizable trays, such trays can be difficult for a non dental practitioner to use, have poor fit, and have had little market acceptance.
Non-customized trays lack features corresponding to a user's unique dentition but can be made to roughly approximate the size and shape of a variety of differently sized and shaped dental arches. A major drawback of non-customized trays is poor fit. Thicker walled trays can be bulky, uncomfortable and often have large gaps between the side walls and the user's tooth surfaces. Thinner, more flexible trays can better adapt to the shape of a user's teeth but have their own drawbacks. The thinnest and most comfortable of such trays can be flimsy and difficult to install and are more easily dislodged during use compared to custom-fitted trays or more rigid non-customized trays. Thin-walled trays made from materials that are sufficiently rigid and/or resilient so as to better maintain their tray-like shape and facilitate installation over a user's teeth tray are less adaptable and have tray walls that are more likely to pull away from a user's teeth during use, particularly the lingual wall. This can be both annoying to the user and permit ingress of saliva into the trough, which can cause diffusion of treatment composition into the person's oral cavity.
Conventional dental treatment strips typically comprise a flexible plastic barrier layer coated or impregnated with a treatment composition on the side of the strip facing the user's teeth. To install the strip, a portion of the strip is placed over the front surfaces of the user's teeth and the remainder is folded around the occlusal edges of the teeth and against the lingual surfaces. A drawback of strips is that they are generally more difficult to install over a user's teeth in the proper location compared to trays, which already have a trough into which the teeth are to be placed, which directs correct installation. Nevertheless, a properly placed strip can remain in place and provide a high level of comfort during treatment, perhaps even more comfort than a dental tray. An improperly placed strip, however, can fail to properly cover all tooth surfaces to be treated, may require adjustment, and can permit treatment composition to rapidly diffuse into the user's oral cavity. Moreover, strips with less adhesive treatment compositions are prone to slip off the teeth during use as a result of even minimal movement of the user's mouth, jaw or tongue. It is usually recommended that users not eat, drink, smoke or sleep while wearing the treatment strip. In some cases, the strip can become so dislodged or mangled that it must be removed and replaced with a fresh strip to complete the desired treatment.
Ultimately, the main impediment to successful treatment is the failure of a user to complete the prescribed treatment regimen. If the treatment apparatus is uncomfortable to wear, difficult to install and/or is prone to prematurely dislodge from the user's teeth, the user may simply give up and prematurely abort the prescribed regimen. Thus, even if dental treatments are possible using a particular treatment apparatus or method, they are less likely to be properly completed if the inadequacies of the treatment apparatus or method cause a user to become discouraged before the desired results are attained.